A Base Station (BS) performs scheduling using power headroom information of an MS in order to efficiently utilize resources of the MS in a wireless communication system. That is, when the MS provides power headroom information to the BS, the BS may estimate maximum uplink transmission power supportable by the MS based on the power headroom information of the MS, and perform control uplink power using such items as Transmit Power Control (TPC), a Modulation and Coding Scheme (MCS) level, a bandwidth, etc. within a range that does not depart from the estimated uplink maximum transmission power.
A network structure that offloads explosively increasing data by additionally installing a small cell network to an existing wireless communication system, such as, a macro cellular network with consideration of a phenomenon that an amount of mobile traffic data increases rapidly is widely used.
For example, a structure that additionally installs a plurality of BSs having a small cell whose transmission region is small, such as a pico cell or a femto cell to a cell region of a macro BS is being provided. In this case, a User Equipment (UE) may wirelessly connect to the macro BS and a small BS simultaneously, and perform uplink transmission to a plurality of BSs that are being connected wirelessly. However, in the related art, only a power headroom report method for controlling uplink transmission power of a UE in the case where the UE is being connected to one BS is provided, and a power headroom report method for controlling uplink transmission power of a UE in the case where the UE is being connected to a plurality of BSs has not been provided. Also, in the case where a plurality of BSs perform wireless resource allocation, the wireless resource allocation is correlated complexly by the medium of the UE, so that complexity for optimizing wireless resource allocation is increased. Furthermore, optimization via real-time information sharing between BSs is required. However, when a circuit (X2) between BSs is actually implemented, a delay time is generated, so that performance deteriorates.
Therefore, an uplink power headroom report method of a UE connected to a plurality of BSs needs to be provided.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.